Home made projector!

[Chernobyl]

Originally Posted by luke_t

Afternoon!

Right, yesterday I took to my setup and lowered my LCD panel to just 5mm from the ohp screen, I funneled the air from the fan through this gap. I thought that the screen might get hotter due to it being closer to the ohp surface... however the reduced space for the air to flow through meant that the air flows through faster and the hottest part of the screen is now only 31 degrees!

I also darkened any areas where like might escape from the edges. After feeling quite please with myself I decided to put the projector to the back of my room.

After refocusing the lense the result was a screen that was massive and sharp! As seen on the picture (again sorry for the poor quality of image) from corner to corner I measured it to be 3m!!!

However at the moment its the creamy colour of my wall that really lets it down. I'll definetly get some Delux brilliance white paint this weekend, hopefully that will improve things!

In case anyone is interested there is a 3M 9550 on ebay in the UK at the moment... http://cgi.ebay.co.uk/ws/eBayISAPI.d...868757875&rd=1
The chap who is selling it goes on to advertise it as a 9700 but from the photos its definetly a 9550.

I'm also hoping that when I get a new bulb it will improve the colour distortion I'm getting, currently very bright at the top, perfect in the middle and very dark at the bottom.

Excellent news with the cooling, I need to check if I have enough air back pressure to achieve the same. Although....
Having too small a gap means I cant poke a cloth in there to clean the dust.
At some point when the Air system is finished I will be using some ladies tights to filter the air. It may be something you wish to consider too.

I've found there is no problem focussing at any distance, but brightness does suffer a lot as you make it bigger. Its best to check while playing a dark movie to see if you get any loss of detail, rather than using Windows, as Windows is always real bright.
Ultimately, theres no way to decide how bright it is until you have the screen you will be using.
I have found my 4000 Lumen OHP to be sufficient for a 5ft diagonal screen without loss if detail on the darkest of dark movies. It can go much bigger for gaming and in Windows and perhaps to 6ft in dark movies too.

The colour/brightness distortion you have may be partially due to the position of the bulb. The bulb filament/bright spot should be in the centre of the rear reflector. Mine isnt quite, causing the top to be darker than the bottom of the screen. All will be sorted out when the new bulb comes (havent ordered yet).

Since I was last online I've made a prototype shroud for the LCD screen, Here's a couple of photos. It was pretty easy to make, involving measuring basic sizes and then cutting the cardboard to shape. It is taped together with Duct tape which lasts a long time!! My air box for the PC water cooler is about 8 months old now and a prototype that is still running too

It may be preferable to drape black material round then stitch it into shape. Something I will try later.

[fearless joe]

interesting, be im sure you know this but thats gona trap heal if you make it surround the top compleatly,
as for the person that sugested led's yes they are brighter then torch bulbs, but stronger then a 400 watt hallogen, err no, i dont think that would work, not unless you had a thousend of them, having said that, that might be a lot cheaper, but i still think thats a bit of a non starter
i still havent got a screen, been bogged down with work for 3 weeks now, but im gona get one soon
joe

[Chernobyl]

Originally Posted by jcw122

first...are there overhead projectors that are bigger than 15"? cause then thad be awesome for someoen to make one with say...a 19" LCD (14-15 inchers have disadvantages compared to these)

seconddly...i keep seeing stuff about people needing bulbs... and about heat stuff. Why not wire the inside so u can use high-brightness LED's? LED's last long...their SUPER bright...and don't throw off much heat (WAAAY less than normal bulbs and crap) I'd REALLY love to see someone use LED's instead of normal bulbs...of course u would need something to power the lower voltages ...dunno how u would do that. You would also need a small bundle of LEDs (not just 1)...not sure how many would be needed though....i REALLY HOPE SOMEOEN TRIES THIS!

Hi jcw
sorry I missed your post.

I havent found any larger OHP's, they are designed to take standard size acetate sheet and all seem to be the same size.

I spent quite a while researching LED lighting and there are numerous problems associated with doing this.

Ideally you want a point source of light, there is no LED powerful enough for this. You can focus the light with a BIG lense though.
You will need a lot of LEDs to match the light level of the Metal Halide systems as Joe mentioned. Metal Halides are up to 3 times more efficient than a Halogen bulb used in most OHP's.
Should you get enough LEDs to produce the brightness levels you want, you will be flat broke

The rating system of LEDs in Lumens is not comparable to the rating of a bulb as the bulb emits the light power all round, not just in a 30 or 60 degree arc.
A 20 Lumen LED is less powerful than a 20 Lumen bulb with a reflector behind it (edit: sorry thats a bit off the wall! "A bulb with a reflector behind it should be compared with the LED" is how it should have been said. I dont have any data to say which is the brightest for the same rating).

LEDs do still produce a fair heat/Watt which can cause sudden failure of the LEDs if bunched tightly and not cooled adequately. Not a real problem, but one should consider the number of LEDs required and the the cooling method needed.

This is a good concise answer why LEDs arent much use in high power applications:
http://www.marktechopto.com/engineering/white.cfm

Its a nice idea to use white LEDs and maybe sometime soon can become a reality. Efficient white LEDs havent been around long, so big advances should be coming. Any significant advance in white LED technology will have huge repercussions on the world and is likely to become mainstream news, keep yer eyes peeled!

[Chernobyl]

Originally Posted by fearless joe

interesting, be im sure you know this but thats gona trap heal if you make it surround the top compleatly,
as for the person that sugested led's yes they are brighter then torch bulbs, but stronger then a 400 watt hallogen, err no, i dont think that would work, not unless you had a thousend of them, having said that, that might be a lot cheaper, but i still think thats a bit of a non starter
i still havent got a screen, been bogged down with work for 3 weeks now, but im gona get one soon
joe

Hi Joe
to allow the air to escape, I left a whacking great hole in the top

It performs more like a windtunnel now and is at least as effective as blowing air across it! The shroud does absorb some sound too. Sound isnt really an issue, I never think of it when using the projector, but it does have the sound of a low level computer.
The LCD frame is far more solid with the shroud and will be even moreso once the shroud is attached to the LCD frame not just resting on it.

[jcw122]

Iv also found yet another pretty big problem w/ ur projectors (hell these things are awesome though) i was looking at once today...and noticed soemthing "How come the shade of light from the light THROUGH the glass top isnt the same shade as when u look at the bulb through those side vents....THE GLASS ITSELF. OVERHEAD PROJECTOR GLASS ISNT PURE. Look at the glass at side angle...see the green? That denotes impurities. These impurities will degrade the light quality coming from the bulb, this is why the final image color wont be as great, even on a pure white wall. What to do? I dont know where to find pure glass, but i know the process to make it (used for making fiber optic glass) is more expensive...and i dunno where u can find it in such a size as needed. Hope this helps some of ur people's off-white, white color problems

[Cesium]

my lcd died no apparent reason either, just died even though i didnt do anything to it

turned it on and it gave me a dark blue screen with circles and then black would phase over from top to bottom, then it would go into standby mode

[Chernobyl]

Originally Posted by jcw122

Iv also found yet another pretty big problem w/ ur projectors (hell these things are awesome though) i was looking at once today...and noticed soemthing "How come the shade of light from the light THROUGH the glass top isnt the same shade as when u look at the bulb through those side vents....THE GLASS ITSELF. OVERHEAD PROJECTOR GLASS ISNT PURE. Look at the glass at side angle...see the green? That denotes impurities. These impurities will degrade the light quality coming from the bulb, this is why the final image color wont be as great, even on a pure white wall. What to do? I dont know where to find pure glass, but i know the process to make it (used for making fiber optic glass) is more expensive...and i dunno where u can find it in such a size as needed. Hope this helps some of ur people's off-white, white color problems

Hi jcw
I just tried removing the glass but wasnt able to test long enough to see how much difference it made. The LCD became very red in the centre and in a large circle over most of the LCD. I powered it off quick smart and luckily its still working fine

The off white problem is undoubtedly due to the bulb. According to the specs, its colour is firmly yellow. I couldnt expect this bulb to produce a true white as it simply cannot do it. How much influence the glass has (and whether it needs to be considered) could possibly be found out once I get a proper UV/IR filter to replace the glass. The glass seems to be doing a champion job of stopping the light from destroying the LCD, I think I'll leave it there for now
Chances are, a better UV/IR filter will have a stronger colouring effect than the glass has, I've yet to see one. Better glass may make some difference, but at this stage, using the wrong colour bulb is by far the dominating factor.

My hope is that changing the bulb to a Daylight MH (~5500K) will sort out the colour without further modification. And of course the addition of the UV/IR filter which I hope to replace the glass with.
I have found some security plastic sheeting that loses 15% of the light power, but blocks UV and IR light. I am to receive a quote on the cost soon.

ps
pure glass isnt see through and will have a colour tint if its 40cm thick , viewed side on

[Chernobyl]

Originally Posted by Cesium

my lcd died no apparent reason either, just died even though i didnt do anything to it

turned it on and it gave me a dark blue screen with circles and then black would phase over from top to bottom, then it would go into standby mode

Cesium, I'm so sorry, you must be gutted,
You werent by any chance running without any glass (see last post!).

The electronics are very susceptible to static, and even though you dont feel anything, just about every time you touch it, you will give mini static shocks. At the moment, the Earth lines on your PCB's and anything connected to them are preferred routes for static.
To make sure this isnt a concern, I kept all the original housing and shielding for the electronics, making the metal housing into the preferred route for static.

How did you mount your electronics?

[Daniel ~]

Sorry you had a bad day Cesium! I hope you can remedy without to much expense...

[Cesium]

i had everything laying out in the open as i had for 3 weeks sitting on post-it notes and cardboard (had the glass in, surely not a heat related problem)

i thought that would be good enough against shock, but you're right, i was careless and never grounded myself before touching the electronics

[Chernobyl]

Originally Posted by Cesium

i had everything laying out in the open as i had for 3 weeks sitting on post-it notes and cardboard (had the glass in, surely not a heat related problem)

i thought that would be good enough against shock, but you're right, i was careless and never grounded myself before touching the electronics

I hope you can afford to get it running. You will want to after this!!

A friend GAVE me an X2VGA XBox VGA out adapter!
You know who you are, a big thanks dude.
This adapter is astonishing. The XBox looks even better than the PC on screen.

I've attached a few screenshots of the XBox in use.
(As always, it doesnt look as bright on the camera, every detail is there on screen)

The pics are in order:
Sudeki (converted to Xbox by a friend, gooood game)
Leisure suit Larry (tame picture not to offend )
Crouching Tiger XVid (using higher Res 720p mode)

If anyone has a request to see something on the projector, please do say

[Daniel ~]

Now that's AMAZING!

[danrok]

Does look good.

[dantheman]

Hello all,
i must say that i am extremely impressed with the projects on this forum and the vast amount of imformation available.

well after visiting tom's hardware and reading the homemade projector article i have decided i will have a wee go at it myself.

so far i have bought;

- A Samsung Syncmaster 510n (from ebay.co.uk for £80)
- An old overhead projector, 600watt [[still to arrive]] ( ebay.co.uk £43)
- white screen material, apparentley used to black out windows, bought form a small fabric shop in galashiels for £8.

I bought the samsung 510n because it was on the recommended monitor list on tom's h/w.
monitor list

dismanlted the the thing yesterday with success! was worried that i might tottaly break the thing, but i took my time and everything went fine -

so here is how i did it(refer to attached images)

- the first image shows the monitor on its front, with the external casing removed, back metal thingy removed(technical eh) but no connections have ben disconnected yet.
-the second image shows the connections to the backlighting panel have been removed, they will not be connected later because they are no longer needed.
- the third image shows the main video connecion( the cable with loads of wires) has been disconnected. had to be quite careful with this one as it looks quite fragile. also the connection to the control panel circuit has been removed(port at top left of image).
- the fourth image shows me removing the plastic that was keeping the lcd pcb stuck onto the back of the backlighting unit. came off really easy. made sure to keep myself static free by using anti static bags. gotta be careful with
the connecting filmy bits though - i suspect they could be easily damaged.

so image five shows you what i am down to!! not going to take the actual screen part out until the ohp arrives. also note that i have kept all the additional circuits on the metal frame they were already on. this should hopefully keep them grounded and easier to mount on the ohp.
the actual screen part is in a nice plastic frame!! it surrounds the screen and i think i may just leave this on...
i used metal hoop things to mount my material on the wall, will need to steam the material to get rid of the creases because i dont think i can iron it directly.

to be continued....

[danrok]

Ah! Another projector!

[Chernobyl]

Originally Posted by dantheman

Hello all,
i must say that i am extremely impressed with the projects on this forum and the vast amount of imformation available.

well after visiting tom's hardware and reading the homemade projector article i have decided i will have a wee go at it myself.

so far i have bought;

- A Samsung Syncmaster 510n (from ebay.co.uk for £80)
- An old overhead projector, 600watt [[still to arrive]] ( ebay.co.uk £43)
- white screen material, apparentley used to black out windows, bought form a small fabric shop in galashiels for £8.

I bought the samsung 510n because it was on the recommended monitor list on tom's h/w.
monitor list

dismanlted the the thing yesterday with success! was worried that i might tottaly break the thing, but i took my time and everything went fine -

so here is how i did it(refer to attached images)

- the first image shows the monitor on its front, with the external casing removed, back metal thingy removed(technical eh) but no connections have ben disconnected yet.
-the second image shows the connections to the backlighting panel have been removed, they will not be connected later because they are no longer needed.
- the third image shows the main video connecion( the cable with loads of wires) has been disconnected. had to be quite careful with this one as it looks quite fragile.
- the fourth image shows me removing the plastic that was keeping the lcd pcb stuck onto the back of the backlighting unit. came off really easy. made sure to keep myself static free by using anti static bags. gotta be careful with
the connecting filmy bits though - i suspect they could be easily damaged.

Hehe, cool.
wow, I didnt realise that any of the monitors recommended by Toms were 16mS. Excellent buy!
Can you tell us how good you find it is for gaming?

Following Cesiums project, it appears his failure may have been due to static.
Will you be remounting the electronics on the metal cage again to help prevent this or have you another plan?
Which OHP did you get? That is damn cheap!

Thanks for posting

[dantheman]

Hehe, cool.
wow, I didnt realise that any of the monitors recommended by Toms were 16mS. Excellent buy!
Can you tell us how good you find it is for gaming?

Following Cesiums project, it appears his failure may have been due to static.
Will you be remounting the electronics on the metal cage again to help prevent this or have you another plan?
Which OHP did you get? That is damn cheap!

Thanks for posting
__________________

wow fast reply!!!

yeh i am really aware of the static problem, might build some sort of fibreglass casing for the whole thing when its finished. think i will definately keep the circuits on the metal frame they were on because it keeps them together and hopeully they are less likely to get static shocked this way.
sorry but i dont know the make of the ohp, quite an old one but i know that it def has a 600watt bulb which might be nice. yeh i was amazed at the price of both. monitor seems top quality - really nice picture, colour and viewing angle is suberb!!!

here is a pic of my creased screen which is 2m wide.
ohp should arrive anytime this week!

[dantheman]

i have a question !!

i want to use an old pc power supply to power my cooling fan, but i dont think it'l power the fan until it is connected to a motherboard!!!. is there anyway i can get around this?

also what is the best size of fan to be using?

cheers Dan

[Chernobyl]

Originally Posted by dantheman

Hehe, cool.
wow, I didnt realise that any of the monitors recommended by Toms were 16mS. Excellent buy!
Can you tell us how good you find it is for gaming?

Following Cesiums project, it appears his failure may have been due to static.
Will you be remounting the electronics on the metal cage again to help prevent this or have you another plan?
Which OHP did you get? That is damn cheap!

Thanks for posting
__________________

wow fast reply!!!

yeh i am really aware of the static problem, might build some sort of fibreglass casing for the whole thing when its finished. think i will definately keep the circuits on the metal frame they were on because it keeps them together and hopeully they are less likely to get static shocked this way.
sorry but i dont know the make of the ohp, quite an old one but i know that it def has a 600watt bulb which might be nice. yeh i was amazed at the price of both. monitor seems top quality - really nice picture, colour and viewing angle is suberb!!!

here is a pic of my creased screen which is 2m wide.
ohp should arrive anytime this week!

Places like Maplins and RS sell plastic boxes used for putting little electronics projects in and fitting knobs and switches to. A big one of these without its lid may be perfect to fit over the electronics.
At RS: http://rswww.com (cant post the whole link, they make it tough for you)
All Products | Electrical | Enclosures - Metal & Plastic | ABS Boxes
There are some RF shielded boxes which sound just the ticket. Largest Box is 19x11x6cm
There are also many other boxes at very good prices.

http://www.maplin.co.uk/Search.aspx?...%20box&doy=8m2
has many, but they dont list the box sizes! Not sure how they sell any.

I just saw your post on hotwiring your PSU
If you connect the green wire to a black wire, it should come on.
Its not wise to run a PSU without a load, so make sure your at least your fan is plugged in.

I'd really like to know if your screen material is a good screen. One thing that counts: when you play a film and there are shiny objects, they should look at least a bit shiny, not dullish. ie shiny metal, reflections on glass should look bright.
There is a lot of effort being put into finding good screens cheap, I hope you have hit on one

Edit: I'm using 2x120mm fans at 7V instead of 12V. to achieve this, move the outer black wire to the hole of the red wire. Leave the yellow wire in place. This makes earth=5V and Vhigh=12V, giving 7V across the fan(s).
Once you have modded one fan for 7V, plug the other fan straight into the connector from your first fan and it will also be 7V.

You can use smaller fans, but to achieve the same airflow they need to run faster and make more noise. There are exceptions to the rule, but they cost more.

[dantheman]

thanks for the fan info, think my fan only has red and black cable... will give it a go anyways. think i'll get the 2 12mm fans - sounds like a good idea. are they quite quite?


i'll post all my results as and when they happen, got hl2, doom3 so i'll maybe use them for some gaming screens!!